The Appalachian Mountains and surrounding residential and agricultural lands
represent fire hazards.
This might sound minor because forest and residential fires happen all the time; however, not all at once.

The resource targeted is the highway system.
Disrupting transportation can cause billions in damages due to delays alone.
Residential and commercial properties are at risk.
However, destroying agricultural harvests presents a greater danger.
These all cause massive financial damages.
California's agricultural industry presents a large target as well.

Security at small airports is minimal.
Cessnas have long range and do not require airfields,
typically used by farmers for pest control.
Just four of these airplanes could set twenty States and two Canadian Provinces on fire
in a single night.

The terrorists do not even have to import military grade incendiary devices.
Everything can be purchased locally.
Sparklers make good fuses and burn very hot, 1000°C.
This is sufficient to ignite shredded rubber tire which burns at 500°C.

Bags of shredded tires can be purchased at any hardware store, commonly used for playgrounds and landscaping.
Contained in a simple plastic cup that bursts on impact,
the burning shards of rubber ignite vegetation and roofs which burn at 300°C.

Sparklers do not resemble like weapons of mass destruction,
but a cluster of these will flare, quickly releasing their high energy.
Their thermal reaction feeds off each other to create a sustained heat flash to ignite the shredded rubber which is difficult to extinguish.

Four planes could realistically drop two-thousand small improvised incendiaries in their zones.
During their four to six hours of flight time, all of the Appalachian Mountains could be set on fire.
Eight thousand small camp fires would grow by morning into major fires.
By lunchtime, these fires would cluster into firestorms.
Similar to fire bombing Japanese cities in WWII.

There is no security preventing this firestorm.
Eight terrorists could make it happen.
The Appalachian Mountains represent a resource-terrorism target.